Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

Despite offering low-carbon and reliable energy, the utilization of nuclear energy is declining globally due to high upfront capital costs and longer returns on investments. Nuclear cogeneration of valuable chemicals from waste biomass-derived feedstocks could have beneficial impacts while harnessing the underutilized resource of ionizing energy. Here, we demonstrate selective methanol or acetaldehyde production from ethylene glycol, a feedstock derived from glycerol, a byproduct of biodiesel, using irradiations from a nuclear fission reactor. The influence of radiation quality, dose rate, and the absorbed dose of irradiations on radiochemical yields (G-value) has been studied. Under low-dose-rate, γ-only radiolysis during reactor shutdown rate (<0.018 kGy min–1), acetaldehyde is produced at a maximum G-value of 8.28 ± 1.05 μmol J–1 and a mass productivity of 0.73 ± 0.06% from the 20 kGy irradiation of neat ethylene glycol. When exposed to a high-dose-rate (6.5 kGy min–1), 100 kGy mixed-field of neutron + γ-ray radiations, the radiolytic selectivity is adjusted from acetaldehyde to generate methanol at a G-value of 2.91 ± 0.78 μmol J–1 and a mass productivity of 0.93 ± 0.23%. Notably, utilizing 422 theoretical systems could contribute to 4.96% of worldwide acetaldehyde production using a spent fuel pool γ-ray scheme. This research reports G-values and production capacities for acetaldehyde for high-dose scenarios and shows the potential selectivity of a nuclear cogeneration process to synthesize chemicals based on their irradiation conditions from the same reagent

Towards treatment planning and treatment of deep-seated solid tumors by electrochemotherapy

<p>Abstract</p> <p>Background</p> <p>Electrochemotherapy treats tumors by combining specific chemotherapeutic drugs with an intracellular target and electric pulses, which increases drug uptake into the tumor cells. Electrochemotherapy has been successfully used for treatment of easily accessible superficial tumor nodules. In this paper, we present the first case of deep-seated tumor electrochemotherapy based on numerical treatment planning.</p> <p>Methods</p> <p>The aim of our study was to treat a melanoma metastasis in the thigh of a patient. Treatment planning for electrode positioning and electrical pulse parameters was performed for two different electrode configurations: one with four and another with five long needle electrodes. During the procedure, the four electrode treatment plan was adopted and the patient was treated accordingly by electrochemotherapy with bleomycin. The response to treatment was clinically and radiographically evaluated. Due to a partial response of the treated tumor, the metastasis was surgically removed after 2 months and pathological analysis was performed.</p> <p>Results</p> <p>A partial response of the tumor to electrochemotherapy was obtained. Histologically, the metastasis showed partial necrosis due to electrochemotherapy, estimated to represent 40-50% of the tumor. Based on the data obtained, we re-evaluated the electrical treatment parameters in order to correlate the treatment plan with the clinical response. Electrode positions in the numerical model were updated according to the actual positions during treatment. We compared the maximum value of the measured electric current with the current predicted by the model and good agreement was obtained. Finally, tumor coverage with an electric field above the reversible threshold was recalculated and determined to be approximately 94%. Therefore, according to the calculations, a small volume of tumor cells remained viable after electrochemotherapy, and these were sufficient for tumor regrowth.</p> <p>Conclusions</p> <p>In this, the first reported clinical case, deep-seated melanoma metastasis in the thigh of the patient was treated by electrochemotherapy, according to a treatment plan obtained by numerical modeling and optimization. Although only a partial response was obtained, the presented work demonstrates that treatment of deep-seated tumor nodules by electrochemotherapy is feasible and sets the ground for numerical treatment planning-based electrochemotherapy.</p> <p>Trial registration</p> <p>EudraCT:2008-008290-54</p

Observables of interest for the characterisation of Spent Nuclear Fuel

The characterisation of Spent Nuclear Fuel (SNF) in view of intermediate storage and final disposal is discussed. The main observables of interest that need to be determined are the decay heat, neutron and -ray emission spectra. In addition, the inventory of specific nuclides that are important for criticality safety analysis and to verify the fuel history has to be determined. Some of the observables such as the decay heat and neutron and -ray emission rate can be determined by Non-Destructive Analysis (NDA) methods. Unfortunately, this is not always possible especially during routine operation. Hence, a characterisation of SNF will rely on theoretical calculations combined with results of NDA methods. In this work the observables of interest, also referred to as source terms, are discussed based on theoretical calculations starting from fresh UO2 and MOX fuel. The irradiation conditions are representative for PWR. The Serpent code is used to define the nuclides which have an important contribution to the observables. The emphasis is on cooling times between 1 a and 1000 a.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Nuclear-driven production of renewable fuel additives from waste organics

Non-intermittent, low-carbon energy from nuclear or biofuels is integral to many strategies to achieve Carbon Budget Reduction targets. However, nuclear plants have high, upfront costs and biodiesel manufacture produces waste glycerol with few secondary uses. Combining these technologies, to precipitate valuable feedstocks from waste glycerol using ionizing radiation, could diversify nuclear energy use whilst valorizing biodiesel waste. Here, we demonstrate solketal (2,2-dimethyl-1,3-dioxolane-4-yl) and acetol (1-hydroxypropan-2-one) production is enhanced in selected aqueous glycerol-acetone mixtures with γ radiation with yields of 1.5 ± 0.2 µmol J−1 and 1.8 ± 0.2 µmol J−1, respectively. This is consistent with the generation of either the stabilized, protonated glycerol cation (CH2OH-CHOH-CH2OH2+ ) from the direct action of glycerol, or the hydronium species, H3O+, via water radiolysis, and their role in the subsequent acid-catalyzed mechanisms for acetol and solketal production. Scaled to a hypothetically compatible range of nuclear facilities in Europe (i.e., contemporary Pressurised Water Reactor designs or spent nuclear fuel stores), we estimate annual solketal production at approximately (1.0 ± 0.1) × 104 t year−1. Given a forecast increase of 5% to 20% v/v% in the renewable proportion of commercial petroleum blends by 2030, nuclear-driven, biomass-derived solketal could contribute towards net-zero emissions targets, combining low-carbon co-generation and co-production

Recommendations for MYRRHA relevant cross section data to the JEFF project

Within the framework of Work Package 10 of the EC FP7 CHANDA project, nuclear data of importance for the operation of MYRRHA, a lead-bismuth cooled accelerator driven reactor under development at SCK•CEN (BE), were studied. Based on data in the main nuclear data libraries, i.e. JEFF, JENDL, ENDF/B and BROND, and in the TENDL and CIELO libraries and on experimental data reported in the literature, recommendations to the JEFF project were made for several nuclides of interest to the MYRRHA reactor.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Determination of lethal electric field threshold for pulsed field ablation in ex vivo perfused porcine and human hearts

IntroductionPulsed field ablation is an emerging modality for catheter-based cardiac ablation. The main mechanism of action is irreversible electroporation (IRE), a threshold-based phenomenon in which cells die after exposure to intense pulsed electric fields. Lethal electric field threshold for IRE is a tissue property that determines treatment feasibility and enables the development of new devices and therapeutic applications, but it is greatly dependent on the number of pulses and their duration.MethodsIn the study, lesions were generated by applying IRE in porcine and human left ventricles using a pair of parallel needle electrodes at different voltages (500–1500 V) and two different pulse waveforms: a proprietary biphasic waveform (Medtronic) and monophasic 48 × 100 μs pulses. The lethal electric field threshold, anisotropy ratio, and conductivity increase by electroporation were determined by numerical modeling, comparing the model outputs with segmented lesion images.ResultsThe median threshold was 535 V/cm in porcine ((N = 51 lesions in n = 6 hearts) and 416 V/cm in the human donor hearts ((N = 21 lesions in n = 3 hearts) for the biphasic waveform. The median threshold value was 368 V/cm in porcine hearts ((N = 35 lesions in n = 9 hearts) cm for 48 × 100 μs pulses.DiscussionThe values obtained are compared with an extensive literature review of published lethal electric field thresholds in other tissues and were found to be lower than most other tissues, except for skeletal muscle. These findings, albeit preliminary, from a limited number of hearts suggest that treatments in humans with parameters optimized in pigs should result in equal or greater lesions

Uporaba hibridnih metod za transport nevtronov in analizo občutljivosti

Accurate and efficient determination of uncertainties of physical quantities is a necessary step of any experiment or computational analysis. Uncertainties in particle transport simulations can be divided by type, statistical or systematic, and by origin i.e. uncertainties in nuclear data and uncertainties originating from approximations. Specifically in neutron transport simulations of fusion and fission shielding applications the approximations can be attributed to geometry and material specification, numerical (discretization of the phase space) approximations of deterministic transport methods and statistical uncertainty of stochastic transport methods. Accurate knowledge of all uncertainties related to transport simulations leads to reduced safety margins and consequently to more efficient experimental and commercial designs. The thesis is focused on developing new methods for efficient propagation of nuclear data uncertainties and reducing the statistical uncertainties of stochastic transport methods with hybrid transport methodologies. The first chapter of the thesis gives an overview of all theoretical aspects of neutron transport, variance reduction, hybrid methodologies and nuclear data (ND) sensitivity and uncertainty (SU) quantifications. The second chapter contains the description and evaluation of computer codes used in the thesis. An extensive evaluation and validation of the ADVANTG hybrid code is presented in this part. Besides the deterministic approach to ND uncertainty quantification the stochastic approach is also evaluated and used for validation purposes. In the last chapter the main contributions to the scientific field by the thesis author are presented. A large emphasis is given to the work that was done to develop a user friendly and efficient code system ASUSD (ADVANTG + SUSD3D) for ND S/U quantification. The code system enables ND S/U analysis of complex shielding experiments which was previously cumbersome, computationally expensive or even impossible. The ASUSD code system was validated and applied to two complex fusion experiments including the challenging nexp streaming benchmark experiment. Moreover ASUSD was used to asses the effect of self-shielded cross sections on the effectiveness of variance reduction parameters. The final contribution to the scientific field of hybrid particle transport is the development of a new method for determining variance reduction parameters based on sensitivity profiles - saber. SABER preforms similarly or better than the current established methodologies.Točno in učinkovito določanje negotovosti fizikalnih količin je nujen korak vsakega eksperimenta ali računalniške simulacije. Negotovosti na področju simulacij transporta delcev lahko delimo glede na tip, na sistematične oziroma statistične, in glede na izvor npr. negotovosti v jedrskih podatkih oziroma negotovosti, ki izvirajo iz približkov. Specifično pri simulacijah transporta nevtronov fuzijskih in fisijskih aplikacij radiološkega ščitenja lahko približke dodelimo specifikacijam geometrijskega modela in materialne sestave, numeričnim aproksimacijam (diskretizacija faznega prostora) pri determinističnih metodah in statističnim negotovostim, ki se pojavijo pri stohastičnih metodah za transport delcev. Točno poznavanje vseh negotovosti povezanih s simulacijami transporta delcev privede do zmanjšanja varnostnih faktorjev in posledično bolj učinkovitih eksperimentalnih in komercialnih zasnov. Disertacija je osredotočena na razvoj novih metod za učinkovito propagacijo negotovosti jedrskih podatkov in zmanjšanje statistične negotovosti pri stohastičnih simulacijah transporta delcev s hibridnimi metodologijami. Prvo poglavje disertacije povzema vse teoretične vidike transporta nevtronov, redukcije variance, hibridnih metodologij ter določanje občultjivosti in negovosti (O/N) zaradi jedrskih podaktov (JP). Drugo poglavje vsebuje opis in evalvacijo programov, ki so bili uporabljeni v disertaciji. Predstavljena je tudi obsežna evalvacija in validacija hibridne kode ADVANTG. Poleg determinističnega pristopa k O/N zaradi JP, je za namene validacije predstavljen tudi stohastični pristop k določevanju negotovosti zaradi JP. V zadnjem poglavju so predstavljeni glavni doprinosi avtorja disertacije znanstvenemu področju. Velik poudarek je namenjen predstavitvi razvoja uporabniku prijaznega in učinkovitega programskega paketa ASUSD (ADVANTG + SUSD3D) za O/N zaradi JP. Programski paket omogoča analizo O/N zaradi JP kompleksnih aplikacij radiološkega ščitenja, ki so bile do sedaj okorne, računalniško potratne ali celo nemogoče. Paket ASUSD je bil validiran na dveh referenčnih eksperimentih in apliciran na dva kompleksna fuzijska problema, vključno z zahtevnim referenčnim eksperimentom strujanja, JET3-NEXP. Poleg tega, je bil paket ASUSD uporabljen za preučevanje efekta samoščitenih JP na učinkovitost parametrov za redukcijo variance. Zaključni doprinos znanstvenemu področju hibirdnega transporta delcev je razvoj nove metode za določevanje parametrov za redukcijo variance na podlagi občutljivostnih profilov - SABER. SABER deluje enako dobro oziroma bolje kot trenutno uveljavljena metodologija